This is an exploratory proposal (R21) to study molecular regulation of oxidative stress in diabetic cardiomyopathy. Diabetes cardiomyopathy is a major health issue in diabetes patients. There is an increased mortality and morbidity of heart failure among diabetes patients. How diabetes cardiomyopathy occurs is not yet clear, in part because there is a lack of understanding on the basic mechanisms and a lack of adequate in vitro and in vivo experimental models. Our studies on primary cardiomyocytes have shown that high levels of glucose in culture medium increased lipid peroxidation, a hallmark of oxidative stress. Moreover, diabetic myocardium is associated with increased oxidative stress and altered expression of oxidative stress genes. The goals of this proposal are to elucidate the mechanisms through which glucose, insulin, and IGF I modulates oxidative stress of cardiac muscle cells. Both in vitro and in vivo models of diabetic cardiomyopathy will be investigated in this proposal. We plan to fine the effects of hyperglycemia and insulin/IGF I on oxidative stress in cardiac muscle, and to determine how signaling pathways of insulin and IGF improve cardiac muscle oxidative stress. A stress DNA microarray will be used to identify novel components of free radical-regulatory system in cardiac muscle that are modulated by hyperglycemia and insulin/IGF I. Whether genetically manipulating insulin receptor signaling molecules lead to suppression of oxidative stress will be defined. The potential causal relationship between myocardial oxidative stress and ventricular function will be explored. These data will lay proper foundation to further explore whether dysregulation of free-radical modulating genes lead to myocardial oxidative stress and ventricular dysfunction in diabetic myocardium. These studies should generate novel information and facilitate further understanding of the molecular mechanisms of diabetic cardiomyopathy.